Gripping fastening surface

ABSTRACT

In making a self-gripping fastening surface of the type in which two articles are capable of gripping one another with a selfadhering action but which are releasable upon being forcibly pulled apart and separated, a plurality of elongated filamentlike elements or fibrils are cut from a sheet of flexible material and mounted in upstanding position on at least one of the articles to be attached. The free ends of the mounted fibrils are subjected to a treatment, for example by applying a source of heat thereto, capable of causing each of said free ends to bend and curl back on itself to form a terminal hook thereon, whereby when two like articles are pressed together, the hooks on one article will grip the hooks on the other article and vice versa to cause the two articles to become tightly fastened to one another, or the hooks on one article are caused to penetrate and grip the surface of a frangible article.

United States Patent [191 Brumlik 1 1 GRIPPING FASTENING SURFACE [76] Inventor: George C. Brumlik, 154 Upper Mountain Ave, Montclair, NJ. 07042 [22] Filed: Dec. 1, 1972 [21] Appl. No.: 311,300

Related US. Application Data [62] Division of Ser. No. 857,075, Sept. 11, 1969, Pat.

FOREIGN PATENTS OR APPLICATIONS 1,912,744 10/1970 Germany 24/204 X Primary Examiner-Bobby R. Gay Assistant Examiner-Darrell Marquette Attorney, Agent, or FirmEdward F. Levy [57] ABSTRACT In making a self-gripping fastening surface of the type in which two articles are capable of gripping one another with a self-adhering action but which are releasable upon being forcibly pulled apart and separated, a plurality of elongated filament-like elements or fibrils are cut from a sheet of flexible material and mounted in upstanding position on at least one of the articles to be attached. The free ends of the mounted fibrils are subjected to a treatment, for example by applying a source of heat thereto, capable of causing each of said free ends to bend and curl back on itself to form a terminal hook thereon, whereby when two like articles are pressed together, the hooks on one article will grip the hooks on the other article and vice versa to cause the two articles to become tightly fastened to one another, or the hooks on one article are caused to penetrate and grip the surface of a frangible article.

4 Claims, 9 Drawing Figures sets of cut lines 14 and 16 being selected so as to produce elongated fibrils 12 having pointed ends 18 and 20. Although only a fragmentary section of a plastic sheet is shown in FIG. 1, it will be appreciated that the sheet 10 may be much wider, in a vertical direction as viewed in FIG. 1, so that any number of rows of fibrils 12 may be formed merely by continuing both sets of cut lines 14, 16 linearly in one or both directions. Thus, FIG. 1 shows one horizontal row 22 and the top and lower halfs of a top and lower horizontal row 24 and 26 respectively of fibrils 12. It will be apparent that common cut lines 14, 16 separate adjacent fibrils 12 both in a horizontal and vertical direction so that there is no waste of plastic material between adjacent fibrils 12 as they are cut from the plastic sheet 10.

The plastic sheet 10 may be formed by extrusion into a continuous web. Preferably, the cut lines 14 are disposed generally transversely to the general direction at which the plastic sheet or web exits from the extruder die. Thus in FIG. 1, the illustrated fragmentary section 10 of plastic sheet 10 may be part of a continuous web of a predetermined width in which the web exits from the extruder die in a direction running from left to right as indicated by the arrow 25.

It is desirable that the cut lines l4, 16 be disposed generally transversely of the longitudinal axis of the plastic web as described above so that the molecules of the plastic material will be most favorably aligned to achieve the highest degree of resiliency along the longitudinal axis of the fibril 12 for reasons which will become apparent. In this regard, it is observed that the plastic material selected is of the type having long linear molecules which can readily form fibers and that as such plastic is extruded, the longitudinal axes of the molecules will be oriented in a particular direction relative to the general direction of extrusion flow. In the illustrated embodiment, the molecules will be oriented with their longitudinal axes disposed transversely or generally perpendicular to the direction of arrow 24. The linear orientation of the molecules is such that the extruded plastic web tends to have greater resiliency in a direction transverse or perpendicular to the longitudinal axis of the web. Accordingly, upon cutting the fibrils 12 in the manner heretofore described, it will be seen that each fibril 12 will have a greater resiliency along its longitudinal axis, i.e. the vertical axis in FIG. 2, than would be the case if the fibrils 12 were cut with their longitudinal axes parallel to the direction of extrusion flow.

It is desirable to have the greatest resiliency along the longitudinal axis of the fibril 12 so that when a hook 28 is ultimately formed on one longitudinal end of the fibril, as will be described, such hook 28 will tend to retain its shape and return to its hooked configuration, as shown in FIGS. 4 and 5, after any temporary bending tending to open up the hook. It is also advantageous to have the molecules of the plastic material linearly oriented as aforesaid so as to achieve the most favorable tensile strength, elastic modulus, and other mechanical properties for the fibril 12.

As previously indicated, the plastic is selected from that group of plastic materials having long linear molecules which can form fibers. Examples of plastic materials which meet this criteria are nylons, polyacetals, polyesters, cellulose, polyolefins, polyethers, polysulfones and polycarbonates.

As an alternate method of forming the fibrils, a single set of parallel cut lines may be made in the plastic sheet. In such a case, the fibrils would have parallel sides and a substantial constant cross section throughout their longitudinal lengths. The ends of the fibrils may be pointed as desired. Forming the fibrils in this manner would permit production of longer fibrils, thereby making them more readily adaptible for weaving to a fabric or article to which they are ultimately attached as will be explained.

In order to facilitate formation of the hook 28 on one of the pointed ends 18 or 20 of the fibril, for reasons which will be described, the two opposite surfaces of the plastic wheel 10 have different coefficients of expansion and contraction so that when one of the pointed ends of the fibril 21, for example the pointed end 18 in the illustrated embodiment, is treated by heat, flame, chemicals, steam, hot gas jets or the like, the plastic material will curl or curve back on itself at the point of treatment to form the hook 28.

Different coefficients of expansion or contraction on the two sides of the plastic sheet 10 may be obtained in various ways. For example, two plastic sheets 17 and 19 (FIG. 7) of the same or different material but having different coefficients of expansion may be laminated to one another.

Another example of a procedure for obtaining the aforementioned properties in the plastic sheet would be to induce different stresses on one side by treating the latter either chemically or physically. Accordingly, one side of the plastic sheet may be exposed to a source of gas (e.g. cold air or the like) which would result in a different arrangement of molecules on the exposed surface. It will be appreciated that various other treatment procedures may be utilized on one side of the plastic sheet to cause a different arrangement of molecules in crystalline or amorphous regions or to alter the chemical nature of one surface relative to the other so as to achieve the desired difference in the coefficients of expansion or contraction on the two opposed surfaces.

Each of the fibrils 12, upon being cut from the plastic sheet 10, appear as shown in FIG. 2. A large number of substantially identical fibrils can be readily obtained from a web of plastic material by cutting the latter along the cut lines 14, 16 as previously described. As apparent in FIG. 2, each fibril is in the nature ofa small filament having pointed ends 18 and 20.

The fibrils 12 are mounted in upstanding position and in relatively thick profusion on the surface of an article to be fastened. In FIG. 6 there is shown an article 30 which may be a piece of fabric for example, and which has an upper surface 32. The fibrils 12 are applied to the article 30 by embedding or otherwise securing one of the ends of the fibrils 12 in the article as shown in FIG. 6. Accordingly, the fibrils 12 may be applied to the article surface 32 by flocking methods, weaving processes, tufting, knotting, or other securing methods. The application procedure is such that the fibrils 12 are mounted so that they cover the selected surface area of the article 30 in closely spaced random fashion and so that each fibril 12 stands substantially upright from the surface 32 of the article 30. Although the aforementioned description indicated by way of example that the article 30 may be a fabric, it will be understood that the fibrils may be applied to any other material capable of supporting such fibrils by the application method employed.

GRIPPING FASTENING SURFACE BACKGROUND OF THE INVENTION This is a division of application Ser. No. 857,075, filed Sept. ll, 1969, now US. Pat. No. 3,710,425.

The present invention relates to a method of making a self-gripping fastening device attachable to one surface and capable of gripping an opposed surface in a self-adhering action for releasably fastening said surfaces to one another.

A self-gripping fastening assembly is presently marketed under the trademark Velcro" and is employed for releasably fastening fabrics or other articles to each other. Such fastening assembly is commercially provided in the form of pairs of fabric strips which are sewn or otherwise secured to the opposed surfaces of the fabrics or other articles to be attached to each other. The outer surface of one of the strips is covered with rows of upstanding, relatively small, closed loops while the outer surface of the other strip is provided with rows of upstanding fiber-like elements having their ends formed in the shape of hooks. When the two surfaces are pressed together, the hooks on one strip engage and grip the loops on the opposite strip so that the strip surfaces grip one another and the attached fabric or articles are releasably secured to each other.

While such conventional fastening assemblies provide convenient and effective gripping action, they are subject to the disadvantage of being relatively expensive since the formation of the loops and hooks and the mounting thereof on the fabric strips involve costly manufacturing operations. Since the fastening assembly is made up of two different elements, one in the form of closed loops and the other in the form of hooks, it will be appreciated that different manufacturing procedures are required for each of the two different types of elements. Further, since two different elements make up a mating assembly, problems could arise in attempting to replace one part of an assembly made by one manufacturer, for example a part having an adhering strip made up of hooks, with a similar part made by a different manufacturer who might ordinarily supply the desired part with an adhering strip made up of closed loops. It will be apparent that two parts made up of closed loops will not adhere to one another. Thus, it will be appreciated that it is desirable to provide a fastening assembly which is made of two like parts, thereby avoiding the requirement of having to manufacture two different types of fastener elements and avoiding problems associated with insuring that two different types of mating elements are included on the two parts to be attached.

Accordingly, an object of the present invention is to provide a novel and improved method of making a selfgripping fastening assembly which involves an inexpensive manufacturing operation and which is adaptable to present day mass production techniques.

A further object is to provide a method of making a fastening assembly which utilizes relatively inexpensive filament-like elements which are readily cut from a sheet of plastic material and which are adapted to be secured to an article in an upright fashion so that the free ends of the elements may be treated, for example by the application of heat, to form hooks thereon,

whereby said article is adapted to self-adhere to another lilte article.

Additional objects and advantages of the invention will become apparent during the course of the following specification when taken in connection with the accompanying drawings.

SUMMARY OF THE INVENTION A method of making a self-gripping fastening assembly for releasably attaching one article to another comprises initially providing a sheet of flexible material and cutting the sheet into a plurality of elongated filamentlike elements or fibrils. A plurality of these fibrils are mounted in an upstanding position on at least one of the articles to be attached with the fibrils projecting substantially perpendicularly from the article. After the fibrils are mounted, their free ends are subjected to a treatment, for example by applying a source of heat thereto, capable of causing each free end to bend and curl back on itself to form a terminal hook thereon, whereby when the two articles are pressed together, the hooks on one article will grip the other article. To effect formation of the hooks, the sheet of plastic may be provided with different coefficients of expansions on opposite sides thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial plan view of a sheet of plastic material showing vertical and diagonal cutlines by which small fibrils are cut from the plastic sheet.

FIG. 2 is a perspective view of one of the fibrils cut from the plastic sheet shown in FIG. 1.

FIG. 3 is an elevational view of the fibril shown in FIG. 2.

FIG. 4 is an elevational view of the fibril after the end has been treated so as to form a hook thereon.

FIG. 5 is a perspective view of the fibril shown in FIG. 4.

FIG. 6 is an elevational view showing a plurality of fibrils mounted on the surface of an article.

FIG. 7 is a fragmentary, enlarged sectional view of a sheet of laminated plastic from which the fibrils may be made.

FIG. 8 is a perspective view of an alternate embodiment of fibril assembly made inaccordance with the invention, the fibrils being arranged in a row and formed integrally with a mounting strip.

FIG. 9 is a perspective view similar to FIG. 8 but showing the fibrils after they have been treated to form terminal hooks thereon.

DETAILED DESCRIPTION Referring to the drawing, FIG. 1 shows a section of a sheet of plastic material 10 from which a plurality of small filaments or fibrils 12 are adapted to be cut. Each fibril 12 has the configuration of a narrow and elongated parallelogram appearing somewhat diamond shaped as best shown in FIG. 2. The diamond shaped fibrils 12 are obtained from the plastic sheet 10 by cutting the latter along two sets of parallel cut lines disposed at an acute angle relative to one another. In FIG. 1, one set of equally spaced, parallel cut lines 14 are vertically disposed and another set of equally spaced, diagonal parallel cut lines 16 are inclined at an acute angle a relative to the vertical cut lines 14. The two sets of cut lines 14 and 16 intersect one another to form the aforementioned fibrils 12, the angle a between the two After the fibrils 12 are mounted on the article 30, as described above, the outer free ends thereof are treated to cause the latter to bend over to form the hooks 28. It will be recalled that the opposed flat surfaces of the fibrils 12 may have different coefficients of expansion. Accordingly, it will be readily understood that subjecting the outer free ends 18 of the mounted fibrils to a source of heat, for example by passing a flame thereover, will cause each end 18 to curl or curve back on itself to form the hook 28. The reason for this is, of course, that the applied heat causes one side of the free end 18 to expand more than the other side resulting in a physical deformation not unlike that which occurs in a bimetal strip used in a temperature measuring device. It will be appreciated that instead of applying a flame to the free ends 18 of the fibrils 12 to form the hooks 28, heat may be applied by various other means, for example, by applying steam thereto or dipping the free ends in a heated liquid. Alternatively, the free ends 18 may be subjected to chemical treatment to effect formation of the hooks 28. For example, the free ends of the mounted fibrils 12 may be dipped in an appropriate chemical until the desired physical deformation required to form the hook is achieved.

It is also possible to form the hooks where the fibril surfaces do not have different coefficients of expansion but are uniform. In this case, the top ends of the fibrils are softened by heat treating or the like, and the softened top ends are bent into hooks, as by applying a strong jet of air thereto.

The finished fastening assembly is thus illustrated in FIG. 6 as comprising a plurality of fastening members or fibrils 12 mounted in closely spaced relationship upon the surface 32 of the article 30 in an upstanding position substantially normal to the surface 32. Each of the fastening elements 12 comprises a generally straight filament like body member having one end embedded or otherwise secured in the article 30 and its other free end terminating in a hook 28 having a free end generally depending back toward the surface 32 of the article 30.

The surface 32 of the article 30 may now be pressed into engagement with the surface of another like article or with the surface of a frangible article, and the two articles will releasably adhere to one another. When two like articles are pressed together, the hooks 28 of one article will grip the hooks of the opposed article and vice versa so that the combined gripping action of the multitude of hooks will cause the articles to become tightly fastened to each other until they are forcibly pulled apart or separated. The surface of article 30 can also be made to adhere to the surface of a frangible article which can be penetrated by the hooks 28. Frangible surfaces which can be engaged and gripped by said hooks are felt, woven and non-woven fabric paper, leather, hair, fur, etc.

In this regard, it will be apparent that the books 28 will tend to open up momentarily to release the articles when the latter are pulled apart. However, it will be recalled, the molecules of the plastic material are oriented to effect greater resiliency along the longitudinal axis of the fibrils so that this greater resiliency is utilized to facilitate return of the hooks to their normal, unopened, configuration. This, of course, facilitates continued reuse of the fastening assembly.

FIGS. 8 and 9 illustrate an alternate manner of forming the fibrils of the present invention, whereby the fibrils are made integral with a mounting strip. For this purpose, a sheet of plastic material is cut or stamped to provide a fibril assembly 40 consisting of an elongated strip 42 from which projects a row of integral triangular fibrils 44. The fibrils 44 may be slightly spaced from each other, or their bases may be contiguous, as shown in FIG. 8. The mounting strip 42 may have a longitudinal fold line 46 along which is bent a perpendicular flap or panel 48 for purposes to be presently explained.

The assembly 40 may be formed from a plastic sheet having its molecules oriented to enhance the resiliency of the formed fibrils 44 as previously described. Further, the plastic sheet and the assembly formed therefrom has opposite surfaces of different coefficients of expansion or contraction, as previously described, so that when suitably treated, the free ends of the fibrils 44 will form into hooks. In the embodiment shown in FIG. 8, the assembly 40 is preferably made of two laminated layers of the type illustrated in FIG. 7, wherein the laminated plastic sheets or layers have different coefficients of expansion and will bend upon the application of heat.

FIG. 9 shows the assembly 40 after the free end portions of the fibrils 44 have been treated, as by applying heat thereto, to cause them to bend into the form of hooks 50. These hooks are used in the same manner previously described to grip frangible surfaces or to releasably lock with hooks of an opposed assembly. Because of the difference in coefficients of expansion of the opposite surfaces of the fibrils 44, the hooks 50 are bent in a direction perpendicular to the plane of the assembly 40, as shown.

The assembly 40 may be mounted on an article, for example on a piece of fabric, by sewing the perpendicular flap or panel 48 to the article. If desired, the panel 48 may be eliminated and the mounting strip 42 may be attached directly to the article by cementing, sewing or other suitable means. In any event, it will be appreciated that when the assembly 40 is mounted on an article, a long line of upstanding hooked fibrils is presented for gripping purposes. A group of assemblies may be mounted in spaced parallel rows to cover a relatively wide area. The assembly 40 has particular application for use as a zipper-type closure for clothing or the like.

From the above description it will be seen that there has been described a self-gripping fastening assembly which may be inexpensively manufactured and which utilizes relatively inexpensive fibrils cut from a sheet of flexible material in a manner designed to obtain the most favorable mechanical properties attendent the use of the fibrils in the particular orientation heretofore described.

In the foregoing detailed description, the filaments are described, by way of example, as being made of plastic and cut from a plastic sheet. It is to be understood that the filaments may also be formed of other flexible materials and cut from sheets of thin metal, glass, or other suitable material. 1

While preferred embodiments of the'invention have been shown and described herein, it is obvious that numerous additions, changes and omissions may be made in such embodiments without departing from the spirit and scope of the invention.

What is claimed is:

l. A multi-element self-gripping fastening surface for releasably connecting together a pair of articles, said fastening surface comprising a resilient fastening assembly secured to a surface of at least one article to be releasably connected to an opposing article, said fastening assembly including a flat mounting strip and a plurality of elongated flat filaments formed integrally with said mounting strip and upstanding perpendicularly therefrom in a linear row along a longitudinal edge of said mounting strip, each of said filaments having opposed flat surfaces and a terminal hook at the free end thereof, said hook being bent perpendicularly to the plane of said flat surfaces, the body of each of said filaments having a molecular alignment in a direction parallel to the longitudinal axis of said body, said mounting strip being secured flat against the surface of said one article with said terminal hooks of said filaments exposed above said article surface to form said selfgripping fastening surface, and positioned to engage and grip a confronting surface of said opposing article when the latter is pressed against said self-gripping surface.

2. A self-gripping fastening surface according to claim 1 in which each of said filaments has a substantially flat body having a sharp point at its free end thereof, said free end being bent to form said terminal hook with a sharp point at the end thereof.

3. A self-gripping fastening surface according to claim 1 in which each of said filaments has a substantially flat body in the form of a narrow elongated triangle defining a sharp point at its free end thereof, said free end being bent to form said terminal hook with a sharp point at the end thereof.

4. A self-gripping fastening surface according to claim 1 in which each of said filaments has a substantially flat body comprising a lamination of two plastic materials having different mechanical properties. 

1. A multi-element self-gripping fastening surface for releasably connecting together a pair of articles, said fastening surface comprising a resilient fastening assembly secured to a surface of at least one article to be releasably connected to an opposing article, said fastening assembly including a flat mounting strip and a plurality of elongated flat filaments formed integrally with said mounting strip and upstanding perpendicularly therefrom in a linear row along a longitudinal edge of said mounting strip, each of said filaments having opposed flat surfaces and a terminal hook at the free end thereof, said hook being bent perpendicularly to the plane of said flat surfaces, the body of each of said filaments having a molecular alignment in a direction parallel to the longitudinal axis of said body, said mounting strip being secured flat against the surface of said one article with said terminal hooks of said filaments exposed above said article surface to form said selfgripping fastening surface, and positioned to engage and grip a confronting surface of said opposing article when the latter is pressed against said self-gripping surface.
 2. A self-gripping fastening surface according to claim 1 in which each of said filaments has a substantially flat body having a sharp point at its free end thereof, said free end being bent to form said terminal hook with a sharp point at the end thereof.
 3. A self-gripping fastening surface according to claim 1 in which each of said filaments has a substantially flat body in the form of a narrow elongated triangle defining a sharp point at its free end thereof, said free end being bent to form said terminal hook with a sharp point at the end thereof.
 4. A self-gripping fastening surface according to claim 1 in which each of said filaments has a substantially flat body comprising a lamination of two plastic materials having different mechanical properties. 